Fuel control system



Jan. 5, 1954 Filed Jan. 15, 1946 z 1.\. 5 69. as 6 so 5 76 o 29 25 22 G. R. ERICSON ET AL FUEL. CONTROL SYSTEM INVENTOR. IRVEN E. COFFEY ATTORNEY J 1954 G. R. ERICSON ET AL 2,664,872

FUEL. CONTROL SYSTEM Filed Jan. 15, 1946 2 Sheets-Sheet 2 F I munmmuh INVENTOR. IRVEN E.COFFEY- BYGEORGE R.ERICSON 3 ATTORNEY Patented Jan. 5, 1954 FUEL CONTROL SYSTEM George R. Ericson, Kirkwood, and Irven E. Coffey, St. Louis, Mo., assignors to Carter Carburetor Corporation, St. Louis, Mo., a corporation of Delaware Application January 15, 1946, Serial No. 641,208

17 Claims. (01. 123-179) This invention relates to charge. forming devices for internal combustion engines.

Fuels, such as propane and butane, which are gaseous at normal atmospheric pressures and temperatures, are usually stored in highly compressed or liquid form.

A charge forming device for use with such highly volatile fuels must properly pressure and meter the fuel as well prevent leakage when the engine is not in operation. Where the fuel is to be drawn through the carburetor by engine suction, the problem is increased because of the high volatility thereof.

Accordingly, the main object of the present invention is to provide an engine charge forming device constructed to efficiently utilize highly volatile or gaseous fuels.

Another object is to provide adequate safety means for preventing escape of the gas when the engine is not in operation.

Another object is to provide means for metering highly volatile fuel in accordance with engine suction.

Another object is to supply fuel for starting under conditions when there is insufiicient suction available for causing the delivery of fuel by induction through the main fuel supply passage.

Another object is to provide novel means for enriching the fuel mixture during acceleration which means is especially adapted for use with highly volatile fuels.

Still another object is to provide novel means for controlling the air supply to the carburetor particularly during starting.

These objects and other more detailed objects hereafter appearing are obtained by the devices illustrated in the accompanying drawings in which Fig. 1 is a diagrammatic view showing parts of internal combustion engine fuel and electrical systems embodying the invention.

Fig. 2 is a similar view showing a modification.

' Figs. 3 and 4 are similar views showing still other modifications.

Fig. 1 shows a downdraft carburetor having a mixture conduit 5 provided with a central Venturi tube 6 and a throttle valve 1. The mixture conduit is mounted on the engine intake manifold 8 in the usual manner and forms a part of the engine intake system. Adjacent the mixture conduit there is provided a pressure reducing and heating device 9 which comprises a casing forming chambers I and Illa separated by a horizontal diaphragm Ii. A stationary needle l2 carried by the upper part of the casing controls a central passage I3 in the diaphragm. The diaphragm is urged upwardly by a coiled spring 14 so as to normally close port l3. Upper chamber i0 is connected by a tube [5 to a tank [6 containing a supply of highly compressed fuel such as propane or butane.

Fuel at a much lower pressure is delivered through the passage l8 connected to lower chamber Ilia. In order to counter-act the cooling effect caused by expansion of gases passing through port [3, a coiled tube 19 is mounted in chamber Illa for exposing expanded gases to a heating medium such as exhaust or hot water. A some- What similar pressure reducing and heating device is disclosed and claimed in a co-pending application in the name of Irven E. Coffey, Serial No. 641,207, filed January 15, 1946, and assigned to the assignee of the present application.

A chamber 20 connected with passage [8 has a valve seat port 2| at its upper extremity controlled by a conical valve 22. This valve has a stem 23 connected to a diaphragm 24 mounted in a chamber 25 communicating with chamber 20 through port 2|. A coiled spring 26 urges diaphragm 24 upwardly and normally maintains valve 22 closed.

A passage 28 leads from chamber 25 and has branches 29 and 30. Main fuel supply branch 29 discharges into the mixture conduit through an annulus 3| and ports 32 in the throat of Venturi tube 6. Passage discharges through idling ports 33 located adjacent and slightly posterior to the throttle when closed. Branches 29 and 30 are provided with check valves 34 and 35 opening toward their respective discharge ports so that when dominant suction exists in one branch, the other branch will be closed by its respective check valve. Branch 30 serves for supplying idling fuel to the engine whereas branch 29 delivers the main fuel supply. Idling branch 30 is provided with an air bleed 36 and an economizer restriction 31.

An auxiliary passage 40 connects passage I8 below or anterior to chamber 20 to a valve chamber 4| through a valve seat port 42 and passes through a duct 43 to idling fuel branch 30. Port 42 is controlled by a valve 44 formed as the armature of a solenoid coil 45 and is normally urged closed by a coiled spring 46. The solenoid coil is connected through one blade of double pole switch 41 to ground and through ignition switch 48 and lead 49 to battery 50. The arrangement is such that when both the ignition switch and the double pole switch are closed, the solenoid will be energized and. valve 44 opened to permit the delivery of starting fuel through passage 43 and idle ports 33. The other pole of switch 41 connects battery lead 49 to starter motor 5|. Throttle '1, preferably, will be partly opened during starting.

In order to insure closing of main fuel metering valve-22 when the engine is not in operation, even though spring 26 or diaphragm 24 may be damaged, an additional pring 55 within chamber:

20 bears against the head portion 56 of a stem 5'! projecting from the armature 58 of a solenoid 59. The solenoid, is connected to ground, as at C and through ignition switch 48 to battery lead 49. When the ignition is turned on, armature 58 and head element 55 will be drawn downwardly by the solenoid to compress spring,.551 and permit opening of valve 22 under the influence of engine suction applied through the induction conduit and passage 28. to diaphragm 24.

. Formed on the upper side of diaphragm-24 is a dash pot chamber 65. in which works arather close fitting piston 65 forming an ,upper movable Wall for the chamber, the chamber being provided with .an air bleed 6'. for" charging the ame with air. Diaphragm. forms a lower movable wall for the chamber. A yokelis connected to the diaphragm slidably receives a lateral element 6Q on a rod 10 carried by pistontfi. A second rod -'|I is-pivoted to the piston and to a lever 12, itself :pivotally .carried at 13 .by the short arm M of a bell crank. Lever 12 at, its opposite extremity is .connected by a linkl to an arm l6 mounted on the throttle, shaftand rigidlymovable therewith. The bell crank is permanently pivoted at '1! and has, a long .armi8 connected by a link I9 to a pistontll, working in a cylinder 8| connected .by

apassage .82 to intake conduit 8 posterior to the throttle. This arrangement is such that upon increase of suction inmanifold 8,, bell crank 14, ..arm.,l8 is rotated counter-clockwise to lift lever pivotx'IB and,.through,y.oke 68,. to lift diaphragm :24 and move valve22 towards itsgclosedposition. ..A'coiled spring 583 in cylinder 8I normally urges piston 80 upwardly in a direction to. lowerpivot 113 and :piston 66 and-,permit additionalopening of valve 22.

. In operation, when the ignition and. starter -.switches are both closed, mainmetering valve.j22 will be released by, safetysolenoid59 and auxiliary valve 44 will alsobe opened by solenoid..45. Ordinarily there will be insuflicient suction. trans- I mitted through passageiato affectdiaphrag-m 24- and metering valve ZZ'during cranking, However, a sulficient supply. of fuel for:star,ti ng will 9, will be delivered by induction through one:or

the other of branchpassages 29 and 3Il,'in accordance. with whether the throttle: valve is :opened, or closed, and fuel will be metered by valve 22 in response to suction conditionsin pas- .sage 28 and the mixture conduit. Pistonz8il. and

.cylinder BI and connected part constitute a suction economizer device which tends. to lean out the mixture at high suction in the intakemanifold. In case the throttle valve issuddenlyopened connection II, 12,15 causes piston, 66 to belowered and the air in cylinders. will be. compressed;

so as to urge diaphragm 24 downwardly and momentarily increase the opening of valve 22. The air pressure in chamber 65 will gradually dissipate through air bleed 5'! so that spring 28 returns the diaphragm and valve to it stable position. When the throttle valve is substantially fully opened, element 69 on link will engage the upper extremity-of stem 23 and positively open the valve to provide additional enrichment as long as the throttle remains in this position. {The form in Fig. 2 is similar to that in Fig. 1 but includes some additional elements. Located within a .c,asing.;- 3Q;mounted on tube I3 is a closed '.thermostat.z9l having its outer end anchored to 92 whichrigidly-mounts an arm 93. Thi arm connected by alink 94 to an arm 95 which operates a valve 95 controlling the passage of heat- -ing fluid through the device 9. Thus the heating of the expanded gas in member 9 is controlled by the temperature-of the outgoing gas in passage I8.

Arm 3 lSf2L 1SO connected b a second link -91 110,3418V6E'I98 having an eccentric extremity 99 perature is low.

which-cQQperates-with a lip I00 on throttle operating lever IOI to variably limit the idling position of the throttle valve in accordance with temperature.

In Fig. 3, the auxiliarystarting by-pass for fuel is omitted and a choke valve I05 is mounted off center on a shaft IOB-in'the upper partof mixture conduit Ed. I A thermostatic bi-metallic coil I01 is mounted about the choke shaft so as to yieldingly close the choke valve when the tem- This substantially reduces the air supply and increases the effective suction on the ports 32a available for drawing starting fuel through main fuel branch29. A lever I88 rigid with the choke shaft is connected by a link I09 to a pistonl III which works in a cylinder I I Iconnected at its lower extremity by a passage vIIZ to chamber 25a and; thence throughpassage 28 to the mixture conduit. A coiled spring H3 constantly urges piston III! upwardly, in a direction to close the choke. During the warm-up, period the position of the'choke fluctuatesinaccordance withtheresistance of the thermostat which opposesthe direct actionof, air. flow on the choke and the action on piston I ID of suctiontrans- -mitted through fuel passage branches ;29;and 30.

When the engin reaches normal temperature,

-thermostat 10'! moves the'choke valve to its wide open position and holds it there.

- In Fig. 4', choke shaft ,Illfia has a-detent II5 formed rigid therewith outside the mixing conduit. An arm I I6 rigid with? the throttle shaft connected by a passage I22 to the mixture conduit posterior to the throttle.

In operation,;to start: the engine, the:- throttle valve is moved to a partially-opened position which, through link Ill, and detent I-I5,.closes the choke valve. When the engine starts to run under its own power, suction applied to piston I20 rotate link Hi .to clear detentl I5 .so-that,

, thereafter the throttle'and choke valves are free to move independently of each other.

The invention may be modified in various respects'as will occur to thoseskilledin the'art and 1 the exclusive use of all modifications .as come ,within the, scope oftheappended' claims is contemplated.

. W claim: 1. -In combination with an internal combustion engine having a starter and an induction conduit, a source of highly volatile fuel supply, passage means connecting said source to said conduit, a pair of valves controlling said passage means, a device operable responsive to suction conditions in said passage and conduit for opening one of said valves, and means operatively connecting said starter and said valve and actuatable upon operation of said starter for opening the other valve.

2. In combination with an internal combustion engine induction conduit having a throttle therein, a source of highly volatile fuel supply, passages connecting said source and said conduit and including a main fuel passage and an idling fuelpassage discharging, respectively, anterior and posterior to said throttle when closed, a normally closed valve controlling each of said passages, a device responding to suction in said conduit for opening a first of said valves controlling the supply of fuel anterior to said throttle, a self-starter for the engine, and means operatively connecting said starter and the second valve controlling the supply of fuel posterior to said throttle and actuatable upon operation of said starter to start the engine for opening said second valve.

3. In combination with an internal combustion engine induction conduit having a throttle therein, a source of fuel supply, main and idling fuel passages connecting said source and said conduit, a valve controlling a supply of fuel to said idling passage, an engine starter, and means operatively connecting said starter and said valve and actuatable upon operation of said starter to start the engine to open said valve.

4. In combination with an internal combustion engine induction conduit having a throttle there in, a source of fuel supply, main and idling fuel passages connecting said source and said conduit,

said idling passage discharging through a port located posterior to said throttle when closed, an additional passage connecting said source and said idling port for supplying starting fuel, a valve controlling said additional passage, an engine starter control, and means operatively connecting said starter and said valve and actuatable responsive to operation of said control for opening said valve.

5. In combination with an internal combustion engine induction conduit, fuel supply means, a passage connecting said supply means and said conduit, a valve controlling said passage, spring means urging said valve closed, a device responsive to suction conditions in said conduit for opening said valve, an engine ignition system, and means responsive to energizing of said system for positively counter-acting said spring means.

6. In combination with an internal combustion engine induction conduit, fuel supply means connected to said conduit, a normally closed valve controlling the supply of fuel to said conduit, an engine ignition switch, and means responsive to suction in said conduit and closing of said ignition switch for positively opening said valve.

7. In combination with an internal combustion engine induction conduit, a source of highly volatile fuel supply connected to said conduit, a normally closed valve controlling the supply of fuel to said conduit, a device responsive to suction conditions in said conduit for opening said valve, an engine ignition system, safety means for urging said valve closed, and means responsive to energizing of said system for overcoming said safety means.

8. In combination with an internal combustion engine induction conduit, a source of highly volatile fuel supply, fuel passages extending from said source to said conduit for supplying fuel for normal operation and also for starting, a Valve controlling said normal fue1 supply passage, an engine ignition system, means responsive to engine suction for opening said valve, safety means normally urging said valve closed, means operatively connecting said ignition system and said safety means and actuatable responsive to energizing of said ignition system for overcoming said safety means, a second normally closed valve in said starting fue1 passage, an engine starter control, and means operatively connecting said starter control and said second valve and actuatable responsive to operation of said control for opening said second valve.

9. In combination with an internal combustion engine induction conduit having a throttle therein, supply means for highly volatile fuel, a passage connecting said supply means and said conduit, a valve controlling said passage, 9, first device operatively connected to said valve and said conduit and responsive to suction in said conduit to actuate said valve in an opening direction upon increase in suction in said conduit, and a second device operatively connected to said throttle and said first device to open said valve independent of the action of suction on said first device.

10. In combination with an internal combustion engine induction conduit having a throttle therein, passage means for supplying highly volatile fuel to said conduit, a valve in said passage means, and a fluid charged chamber having a pair of individually movable walls, one of said Walls being operatively connected to said valve and the other wall being connected to said throttle and having a lost motion mechanical connection to said valve whereby actuation of said throttle and said second wall acts through the fluid in said chamber to yieldingly motivate said first wall and said valve and actuation of said throttle in the opposite direction positively shifts said valve.

11. In combination with an internal combustion engine induction conduit having a throttle, a source of highly volatile fuel, a passage connecting said source to said conduit, a valve controlling said passage, a chamber having a movable wall exposed to suction in said passage and connected to said valve for opening said valve, a dash pot chamber on the opposite side of said movable Wall from said passage, a second movable wall for said dash pot chamber, and an operative connection between said throttle and said second movable wall whereby opening of said throttle actuates said second movable wall and yieldingl motivates said first movable Wall and said valve, and further including a lost motion mechanical connection between said throttle and said valve for positively opening the latter responsive to substantially full opening of said throttle.

12. In combination with an internal combustion engine, induction conduit means of the engine, a fuel supply device operatively connected to said conduit means, a normally closed valve for said device controlling the supply of fuel to said conduit means, an engine ignition system including a switch means, and means including an operative connection between said several means and said valve responsive to suction in said conduit means and operation of said igni- 13-. In aoharge forming device for ,an ir te pai 14. The eombination specified in c1aim;1 f in wvvhi ch said, resilient connection is foir meqhby a dashpot device having a pair of movable walls,

one being connected to said thi ottleand thefotlqer being connected to said valve.

15.-The combination specified in. claim 13 f urther including a movable wallexpos ed to suction ,cq iti ns Said. u sup as for De wing said valve.

,16. m Combinatio with an internal compus- J tionengine iriduetion eonduit having aohokeand L a, throttle, ma'inand auxiliary fuel passages dispharging respectively, anterior andl poste ior to said-throttle, a vaiveleontrollirig' said'ai xiliary 1 passage, an} engine starter T control, ii ea'n operativeiy connecting. said oontrol and said'valv e and aet iatable esponsive to opei'atioh of'said coni tro i for oi e mihglsaidi valve, and thermostatic ,n eans for closing said ,ohoke for starting to fir'ovi de, sufficient suction in said conduit du'ring crapking of the engine. to draw starting'foel throiigh 'said auxiliarvpassage.

l 17; In a ehalfge fo m iiig device for an internal em lem en mi e pndmww 5 throttle is pa'z tial lv opened, and .means ofp'gmtive lywconneoted with said donduit arid .aetfi a ble resp ns ve to ,eng'i'n'e 'sii'otion when the engine is ofiefa tirigiuniifl its o w'r'i power 1aIid/ope i'at'ive1y i eoriii'otedWvith'said connection for disabling 10 saidofierativcoiiriection.

. GEORGE, R, ERICSON. YF

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